Optimization of particle bombardment conditions by &#223- glucuronidase (GUS) reporter system in tomato fruit

Fruits of tomato cultivar R-144 (<i>Lycopersicon esculentum</i> Mill. cv. R-144), a variety from Israel, were bombarded on tungsten particles coated with a plasmid containing GusPlus gene that was coded for &#223-glucuronidase (GUS). Peels of target areas of fruits were removed before bombardment, and as such, after 24 h, the effects of different  bombardment parameters were evaluated by comparing the numbersof blue spots which resulted to histological GUS assays. The effects of bombardment pressure, bombardment distance, content of plasmid and bombardment fruit area and fruit maturity stages on GUS expression were investigated. Optimal transient expression of the GusPlus gene was observed after bombardment at 1100 psi, with 0.83 ìg plasmid per shoot, and 6 cm between stop screen and fruit. GUS expression decreased with the process of fruit ripening and increased from fruit shoulder (close tothe end of the stem) to fruit top (blossom end). The highest number of blue spots was 2456.91/ cm2 and was observed in the area of fruit separation zone. As such, the optimized conditions of particle bombardment in this experiment would have significance for its further application in genetic transformation.Key words: Particle bombardment, &#223-glucuronidase (GUS), tomato, fruit, bombardment parameters

Practical Aspects of Automatic Orientation Analysis of Micrographs

Techniques to analyse the orientation of particulate materials as observed in the scanning electron microscope are reviewed in this paper. Emphasis is placed on digital imaging, processing, and analysis methods, but many secondary electron images are not amenable to traditional image processing as adequate thresholding is often difficult to achieve. Evaluation of the intensity gradient at each pixel offers an alternative approach, and this method is described in detail including the latest developments to generalize the technique. Practical points in the acquisition, processing and analysis of the images are considered and several images, including both synthetically generated and actual back-scattered images of soil particle arrangements are presented. A discussion of methods to display the results is included as are possible future developments

Dynamics of dendritic cell maturation are identified through a novel filtering strategy applied to biological time-course microarray replicates

<p>Abstract</p> <p>Background</p> <p>Dendritic cells (DC) play a central role in primary immune responses and become potent stimulators of the adaptive immune response after undergoing the critical process of maturation. Understanding the dynamics of DC maturation would provide key insights into this important process. Time course microarray experiments can provide unique insights into DC maturation dynamics. Replicate experiments are necessary to address the issues of experimental and biological variability. Statistical methods and averaging are often used to identify significant signals. Here a novel strategy for filtering of replicate time course microarray data, which identifies consistent signals between the replicates, is presented and applied to a DC time course microarray experiment.</p> <p>Results</p> <p>The temporal dynamics of DC maturation were studied by stimulating DC with poly(I:C) and following gene expression at 5 time points from 1 to 24 hours. The novel filtering strategy uses standard statistical and fold change techniques, along with the consistency of replicate temporal profiles, to identify those differentially expressed genes that were consistent in two biological replicate experiments. To address the issue of cluster reproducibility a consensus clustering method, which identifies clusters of genes whose expression varies consistently between replicates, was also developed and applied. Analysis of the resulting clusters revealed many known and novel characteristics of DC maturation, such as the up-regulation of specific immune response pathways. Intriguingly, more genes were down-regulated than up-regulated. Results identify a more comprehensive program of down-regulation, including many genes involved in protein synthesis, metabolism, and housekeeping needed for maintenance of cellular integrity and metabolism.</p> <p>Conclusions</p> <p>The new filtering strategy emphasizes the importance of consistent and reproducible results when analyzing microarray data and utilizes consistency between replicate experiments as a criterion in both feature selection and clustering, without averaging or otherwise combining replicate data. Observation of a significant down-regulation program during DC maturation indicates that DC are preparing for cell death and provides a path to better understand the process. This new filtering strategy can be adapted for use in analyzing other large-scale time course data sets with replicates.</p

Mid-Miocene cooling and the extinction of tundra in continental Antarctica

A major obstacle in understanding the evolution of Cenozoic climate has been the lack of well dated terrestrial evidence from high-latitude, glaciated regions. Here, we report the discovery of exceptionally well preserved fossils of lacustrine and terrestrial organisms from the McMurdo Dry Valleys sector of the Transantarctic Mountains for which we have established a precise radiometric chronology. The fossils, which include diatoms, palynomorphs, mosses, ostracodes, and insects, represent the last vestige of a tundra community that inhabited the mountains before stepped cooling that first brought a full polar climate to Antarctica. Paleoecological analyses, 40Ar/39Ar analyses of associated ash fall, and climate inferences from glaciological modeling together suggest that mean summer temperatures in the region cooled by at least 8°C between 14.07 ± 0.05 Ma and 13.85 ± 0.03 Ma. These results provide novel constraints for the timing and amplitude of middle-Miocene cooling in Antarctica and reveal the ecological legacy of this global climate transition

Equilibrium onions?

We demonstrate the possibility of a stable equilibrium multi-lamellar ("onion") phase in pure lamellar systems (no excess solvent) due to a sufficiently negative Gaussian curvature modulus. The onion phase is stabilized by non-linear elastic moduli coupled to a polydisperse size distribution (Apollonian packing) to allow space-filling without appreciable elastic distortion. This model is compared to experiments on copolymer-decorated lamellar surfactant systems, with reasonable qualitative agreement

A model to explain angular distributions of J/ψJ/\psi and ψ(2S)\psi(2S) decays into ΛΛ‾\Lambda\overline{\Lambda} and Σ0Σ‾0\Sigma^0\overline{\Sigma}^0

BESIII data show a particular angular distribution for the decay of the $J/\psi$ and $\psi(2S)$ mesons into the hyperons $\Lambda\overline{\Lambda}$ and $\Sigma^0\overline{\Sigma}^0$. More in details the angular distribution of the decay $\psi(2S) \to \Sigma^0\overline{\Sigma}^0$ exhibits an opposite trend with respect to that of the other three channels: $J/\psi \to \Lambda\overline{\Lambda}$, $J/\psi \to \Sigma^0\overline{\Sigma}^0$ and $\psi(2S) \to \Lambda\overline{\Lambda}$. We define a model to explain the origin of this phenomenon.Comment: 6 pages, 7 figures, to be published in Chinese Physics

Velocity Map Imaging the Scattering Plane of Gas Surface Collisions

The ability of gas-surface dynamics studies to resolve the velocity distribution of the scattered species in the 2D sacattering plane has been limited by technical capabilities and only a few different approaches have been explored in recent years. In comparison, gas-phase scattering studies have been transformed by the near ubiquitous use of velocity map imaging. We describe an innovative means of introducing a surface within the electric field of a typical velocity map imaging experiment. The retention of optimum velocity mapping conditions was demonstrated by measurements of iodomethane-d3 photodissociation and SIMION calculations. To demonstrate the systems capabilities the velocity distributions of ammonia molecules scattered from a PTFE surface have been measured for multiple product rotational states.Comment: 8 pages, 5 figures, to be submitted to journa

Orthogonal polynomials of discrete variable and Lie algebras of complex size matrices

We give a uniform interpretation of the classical continuous Chebyshev's and Hahn's orthogonal polynomials of discrete variable in terms of Feigin's Lie algebra gl(N), where N is any complex number. One can similarly interpret Chebyshev's and Hahn's q-polynomials and introduce orthogonal polynomials corresponding to Lie superlagebras. We also describe the real forms of gl(N), quasi-finite modules over gl(N), and conditions for unitarity of the quasi-finite modules. Analogs of tensors over gl(N) are also introduced.Comment: 25 pages, LaTe

Intrinsic aerobic capacity sets a divide for aging and longevity

&lt;p&gt;&lt;b&gt;Rationale:&lt;/b&gt; Low aerobic exercise capacity is a powerful predictor of premature morbidity and mortality for healthy adults as well as those with cardiovascular disease. For aged populations, poor performance on treadmill or extended walking tests indicates closer proximity to future health declines. Together, these findings suggest a fundamental connection between aerobic capacity and longevity.&lt;/p&gt; &lt;p&gt;&lt;b&gt;Objectives:&lt;/b&gt; Through artificial selective breeding, we developed an animal model system to prospectively test the association between aerobic exercise capacity and survivability (aerobic hypothesis).&lt;/p&gt; &lt;p&gt;&lt;b&gt;Methods and Results:&lt;/b&gt; Laboratory rats of widely diverse genetic backgrounds (N:NIH stock) were selectively bred for low or high intrinsic (inborn) treadmill running capacity. Cohorts of male and female rats from generations 14, 15, and 17 of selection were followed for survivability and assessed for age-related declines in cardiovascular fitness including maximal oxygen uptake (VO&lt;sub&gt;2max&lt;/sub&gt;), myocardial function, endurance performance, and change in body mass. Median lifespan for low exercise capacity rats was 28% to 45% shorter than high capacity rats (hazard ratio, 0.06; P&#60;0.001). VO&lt;sub&gt;2max&lt;/sub&gt;, measured across adulthood was a reliable predictor of lifespan (P&#60;0.001). During progression from adult to old age, left ventricular myocardial and cardiomyocyte morphology, contractility, and intracellular Ca&lt;sup&gt;2+&lt;/sup&gt; handling in both systole and diastole, as well as mean blood pressure, were more compromised in rats bred for low aerobic capacity. Physical activity levels, energy expenditure (Vo&lt;sub&gt;2&lt;/sub&gt;), and lean body mass were all better sustained with age in rats bred for high aerobic capacity.&lt;/p&gt; &lt;p&gt;&lt;b&gt;Conclusions:&lt;/b&gt; These data obtained from a contrasting heterogeneous model system provide strong evidence that genetic segregation for aerobic exercise capacity can be linked with longevity and are useful for deeper mechanistic exploration of aging.&lt;/p&gt